Hi thanks for reporting. I found where this happens in the code and I’ll make a small fix for the next release.
Till then as workaround please use following URL:
http://<ip-address>/pwa
This resolves automatically to the correct /pwa/login2.html path. Another way to open the Phoscon App is from deCONZ itself via the Phoscon App button which also opens the /pwa/login2.html page.